Teenager Fruhvirtova knocks back Williams comparison
Fruhvirtova reached the last 16 in only her second Grand Slam main draw appearance, while Brenda came through qualifying to reach the first round, where she lost to Aliaksandra Sasnovich.
The world number 82 said that while it had been "special" playing at a major tournament with her sister, comparisons with Venus and Serena Williams were more than a little premature.
"Of course, it's an honour, but I wouldn't really compare us to Serena or Venus," Fruhvirtova said after losing to Donna Vekic.
"They're legends of the sport. We always loved to watch them on the court, when we were younger, and they're definitely an inspiration, but we never wanted to copy anyone.
"I don't think it's right to compare us. It's true we're both sisters. We can be good, and we'll see what happens, but I think it's too soon to compare us to Serena and Venus."
Serena Williams won 23 Grand Slam singles titles before hanging up her racket last year, while seven-times major champion Venus missed the Australian Open because of injury.